| Hypochlorous acid is an important active oxygen species and plays a vital role in the biological immune system.However,abnormally expressed hypochlorous acid in the cell can cause different degrees of damage to biological tissues,and cause inflammation,cancer and other diseases.There is another important active substance in the organism,peroxynitrite,which is an important active nitrogen species.Overexpression of peroxynitrite can also cause disease.Therefore,the real-time and accurate detection of hypochlorous acid and peroxynitrite concentration fluctuations in vivo is very important for revealing their role in physiological and pathological processes,and for the early diagnosis of related diseases.In recent years,fluorescence imaging has been widely used in the imaging of biomolecules due to its advantages of noninvasive,high spatial and temporal resolution.Near-infrared fluorescent probes have received widespread attention due to their longer emission wavelength,lower background fluorescence,less light damage to samples,and stronger tissue penetration.Therefore,it is of great significance to construct high-selectivity and high-sensitivity near-infrared fluorescent probes for the detection of hypochlorous acid and peroxynitrite.In this paper,two near infrared molecular fluorescent probes with high sensitivity and good selectivity were designed and synthesized,and they were successfully used to detect HClO and ONOO~-.The specific contents are as follows:(1)In Chapter 2,we selected phenothiazine with active sulfur as the response group and fluorophore.In order to extend the wavelength of phenothiazine,we introduced 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-methylene)malononitrile,2-benzothiazole acetonitrile,4-methyl quinoline modified with sulfonic acid group and 4-methyl 4-methyl quinoline modified with tetraethylene glycol chain.Based on the four electron-withdrawing groups of quinoline,four probes were synthesized and named PTZ-TCF,PTZ-BTA,PTZ-KL,PTZ-KL-PEG.Among them,although the sensitivity of PTZ-KL is higher,the negatively charged sulfonic acid group makes it difficult to enter the cell.And PTZ-KL-PEG not only has high selectivity and sensitivity(detection limit is 8 n M),but also can enter the cells within 15minutes.Therefore,we successfully applied PTZ-KL-PEG to the imaging of endogenous HClO in HeLa cells induced by LPS.(2)In Chapter 3,we designed and synthesized the near-infrared ratio-type fluorescent probe SiRho-HD using silodoramine as the energy donor,Huda dye as the energy acceptor,and a flexible piperazine carbon chain as the connecting arm.Due to the FRET effect,when the probe is excited with a 635 nm laser,the silodhodamine dye transfers energy to the Lake University analogue,the emission wavelength is 750nm,and the energy transfer efficiency of the probe is 76.8%.When the probe reacted with ONOO~-,the xanthene ring structure of the lake analogue was destroyed by ONOO~-oxidation,the FRET effect disappeared,and the emission wavelength was blue-shifted to 680 nm.In PBS solution(pH8.0,10%Et OH),the fluorescence intensity ratio(F680/F750)of the probe is increased by about 19 times,and the detection limit of the probe is 0.36 micromolar.The overall change trend of the photoacoustic spectrum of the probe is consistent with the absorption spectrum.The signal intensity of the photoacoustic spectrum of the probe at 715 nm(PA715)decreased by 3.9 times in the Saturation point,and the detection limit was 1.3micromolar.In addition,because the probe is positively charged and has good fat solubility,it also has better mitochondrial targeting ability.We have successfully applied it to detect endogenous ONOO~-produced in LPS and IFN-γ-stimulated macrophages and cisplatin-stimulated HK-2 cells.In addition,because the probe also has kidney targeting capabilities,we also applied it to the near-infrared fluorescence and photoacoustic dual-mode imaging of the changes of ONOO~-content during the acute kidney injury induced by cisplatin. |
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